Door operating system for elevators



H. V. M CORMICK DOOR OPERATING SYSTEM FOR ELEVATORS March 18, 1941.

2 Sheets-Sheet 1 Filed Jan. 31, 1940 INVENTOR Harv/o 1/ /7 "C m/ckWITNESSES:

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Patented Mar. 18, 1941 UNITED STATES I ar sen PATENT @FFECE DOOROPERATING SYSTEM FOR ELEVATORS Application January 31, 1940, Serial No.316,539

Claims.

My invention relates to elevator door operating systems, and moreparticularly to high speed master door operators for center openingdoors in which a motor mounted on the car is used for operating both thecar door and the hatchway door at any floor at which the car makes astop.

Heretofore, master door operating systems have usually included a doordriving motor on the car, means for driving the car door by the motor, a

clutch connected to the car door for engaging and driving one of thehatchway door sections, and chains so connecting the hatchway doorsections that operation of one section causes operation of bothsections. These systems require a very strong rigid clutch and evenwhere a strong clutch is used, they often break down because of theforce transmitted at high speed. Furthermore, in these systems, themovement of the clutch to push the hatchway door open in one directionexerts a force on the car tending to move it in the opposite direction,thereby pushing the car to one side of the shaft when the hatchway dooris opened and pushing it back again to the other side of the shaft whenthe hatchway door is closed,

thus causing the car to sway objectionably during the opening andclosing operation of the hatchway door.

Therefore, it is an object of my invention to provide a master dooroperating mechanism or system which will permit the use of lightresilient clutching devices which will not go to pieces in operation andwhich will so balance the forces exerted by the motive means on the carthat the operation of the hatchway doors will have no tendency to movethe car in any direction, thus permitting it to remain in its normallysuspended position during operation of the doors.

Another object is to provide a master door operating system in which theoperating force will be so applied, tied together, and controlled thatall of the parts will work harmoniously together thereby absorbing anyminor unbalance of any of the parts and assuring that each part of thesystem completes its motion simultaneously with the other parts. 1

accompanying draw-- show the car and also the hatchway door at one ofthe floor landings, the car being positioned slightly above the landingindicated:

Fig. 2' is a top plan View of the hatchway doo and car door embodied inFig. l;

Fig. 3 is a diagrammatic representation in straight-line style of acontrol system for the door operating motors; and

Fig. 4 is an explanatory representation of the position of the coils andcontact members of the relays embodied in Fig. 3.

Referring more particularly to thedrawings, I have illustrated a sectionof an elevator hatchway having front wall sections 83 and H and sidewalls 52 and 13. The section of the hatchway is taken at a floor landingprovided with a corridor opening between the wall sections i0 and ll,served by a hatchway door l5 comprising a pair of horizontally slidablecenter opening center door sections l6 and H. The door sections areprovided with suitable hangers I8, i9, 20, and 2| by means of which theyare suspended from an overhead door track rail 22 in the usual manner,so that the door sections may slide toward or away from the center inclosing and opening.

A car 25'is illustrated as disposed in the hatchway in a positionsomewhat above the door opening. The car is provided with a car door orgate 25 comprising a pair of center-opening, horizontal, slidable doorsections 27 and 28 suspended from an overhead track rail 29 by aplurality of hangers 33, 3|, 32, and 33 to cover a doorway in the carrepresented by the dotted line 34.

Inasmuch as door hangers are old and wellknown in the art, no furtherdescription thereof will be given. It will also be apparent that thetrack rails for the hangers may be supported in any suitable manner.

The means for moving the doors to their open position and to theirclosed position comprises a pair of electric motors 35 and 31, one foreach car door section, mounted by means of plates 38 on the upper framemember 33 of the car. The motor 3 6 is provided with a shaft Ml on whichis mounted a pulley M over which a driving belt 42, preferably of the Vtype, passes to a driven pulley or wheel t3. The driven pulley ismounted on the outer end of the shaft 4 3', the other end of which maybe supported in any suitable manner onthe car frame member 39. On theouter end of the shaft 44 is mounted a pulley 45 which operates. thedoor section 21 through a V shaped belt 43 and a rubber covered steelcable M The belt 46 passes around the pulley 45 and has its one endsecurely fixed to an arm ll mounted on a horizontal bar 48 secured tothe upper portions of the hangers 30 and 3| on the hatchway door section21. The other end of the belt 46 is seated in an individual groove in asheave 50 and extends through a passage in the bottom of the groove to apoint near the hub of the sheave where it is firmly secured. The sheave50 is fixed on a shaft 52 rotatably mounted on the frame 39. One end ofthe cable 46 is secured to the arm 41 and its other end is wrappedaround a second individual groove in the sheave 58 to a point where itleads through a. hole in the bottom of the groove and is secured to theside of the sheave. When the motor 36 is operated in one direction, itcauses the wheel 43 to drive the belt 46 to pull the door section 21 toits open position. When the motor is operated in the other direction,the belt rotates the sheave 50 to cause the cable 46 to pull the doorsection 21 to its closed position.

A small sprocket wheel 53 is fixed to the shaft 52 for driving asprocket chain 54 which passes over a sprocket wheel 55 mounted on acontroller E.

The V belt 46 insures good driving characteristics and the rubbercovered steel cable 46 with its one end fastened to the arm 41 and itsother end secured to the sheave 50, provides a positive drive foroperating the controller in accordance with the movement of the doorsection. This double groove sheave drive mechanism is illustrated,described and claimed in my copending application Serial No. 315,895,filed January 26, 1940 The motor 31 is mounted on the right-hand side ofthe car in position to drive a V belt which passes over a sheave 6|. Asmall pulley 62 is mounted on the shaft of the sheave 8| for driving a Vbelt 63, one end of which is secured to the upright arm 84 on the bar 65on the hangers 32 and 33. The other end of the belt 63 is wrapped arounda peripheral groove in a sheave 66 from which it passes through a holeto a center fastening 81. A rubber covered steel cable 68 is wrappedaround a second groove in the sheave 66 with one end secured at thefastening 61 and the other end secured to the arm 64. A sprocket wheel10 is mounted on the sheave of the wheel 66 in position to operate achain H which extends over a sprocket wheel I2, mounted on a controllerF. When the motor 31 is operated, it will efiect rotation of the sheave66 to pull the car door section 28 from its closed position to its openposition or from its open position to its closed position.

The motors 36 and 31 should be so connected to the control system thatthey will rotate in opposite directions when the control system isoperated to open or to close the doors, so that both door sections willmove toward each other in closing and away from each other in opening.

The controllers E and F are provided with contact members or switchesdisposed in the control circuit of Fig. 3 for controlling thedeceleration of the motors in accordance with the position and directionof operation of the doors.

A pair of clutches 73 and 14 are provided to cause the hatchway doors atthe floor landing where the car makes a stop to open and close withoperation of the car door (Fig. 2). The clutch 73 comprises an operatingvane 15 mounted on the car door section 21 in position to enter a slot16 in a rubber block 18- mounted on the hatchway door section I8. Theclutch 14 comprises an operating vane 19 mounted on the car door section28 in position to enter a slot 88 in a rubber block 8| mounted on thehatchway door when the car makes a stop at the landing. Hence, it willbe apparent that when the car is at the landing and its doors are movedhorizontally to their open or to their closed position, the vanes 15 and19 in the slots will engage the walls of the blocks 18 and 8| and causethe hatchway door sections l6 and H to open and shut with the car doors.The individual clutch construction is disclosed in Patent No. 2,094,385issued September 28, 1937, and assigned to Westinghouse ElectricElevator Company.

' It is desirable to have the motor driving systems tied together sothat they will absorb any minor unbalance in their operation and assurethat each part of the system competes its motion simultaneously with theother parts. In order to accomplish this, a pair of rubber covered steeltie cables 84 and 85 are mounted on a pair of sheaves 86 and 81 mountedabove the hatchway door sections "5 and II. The cable 84 passes aroundthe sheave 86 and has its upper end attached to the hanger 20 of thedoor section I! and its lower end attached to the hanger I8 of the doorsection Hi. The cable 85 passes around the sheave 8'1 and has its upperend attached to the hanger 20 of the door section l1 and its lower endattached to the hanger 9 of the door section l6. Therefore, when thedoor section I6 is moved from its center position to the left toward itsopen position, the hanger l9 pulls the lower end of the cable 85 aroundthe sheave 8! and thereby causes the upper end of the cable 85 to pullthe hanger 20 and the door section I! open. When the door section I6 ismoved to its closed position, it pulls the cable 84 to cause the doorsection H to move towards its closed position at the same time and atthe same rate of speed as the door section l6. Hence, it is seen thatthe rubber covered steel cables 84 and 85 will cause the hatchway doorsto operate simultaneously in co-operative relation and when the car isat the landing with the operating vanes 15 and 19 in the slots 16 and 80of the rubber blocks 18 and 8|, the whole door operating system will betied together and operate as a unit.

In actual operation, it is practically impossible to make the two motors36 and 31 divide their load exactly equally. Also, as the car assumesvarious positions sideways in the shaft by reason of guide wear, etc.,one of the clutches may engage sooner than the other, at times. Thehatchway doors are synchronized by the cable tie (84 and 85) betweenthem and this automatically causes a proper division of load between themotors as far as it is possible to do so; that is, if one motor draws agreater share of the load than it should, due to engaging its clutchfirst, it slows down and the other motor speeds up, but in so doing ittries to drive its clutch faster and thereby takes more of the loaduntil the total load is properly divided. There will be momentaryexchanges of energy through the shaft door cable tie just suflicient tokeep the system moving and the load divided.

In order to prevent the opening of any of the hatchway doors while thecar is not standing thereat, and also to prevent operation of the carwhile a hatchway door is open, each hatchway door is provided with aninterlock 98. The interlock comprises a locking latch 9| disposed toengage and hold a pin 92 mounted in the upper part of the hanger |9 whenthe door is closed. The latch 9| is provided with a cam surface whichwill cause it to operate over the pin 92 when the door is brought to aclosed position so that "the door section 15 will be automaticallylocked in its closed position. An arm 93 having a cam wheel 94 isprovided for unlocking the interlock when the car makes a stop at afioor. The cam wheel 94 is positioned to be engaged by an operating camor lever (not shown) which may be mounted on the car in any suitableposition to be operated by the attendant or it may be connected forautomatic control by the control system when the car makes a stop at afloor.

Referring now to the diagrammatic representation of the control systemgiven in Figs. 3 and 4, the motor 36 is provided with an armature 36Aand a field winding 36F. The motor 31 is provided with an armature 31Aand a field winding 31F. The armatures are disposed in parallel circuitsconnected to a pair of supply conductors L+ and L. The field windings36F and 31F are also connected in parallel in the same circuit but inseries with the armatures of the motors. A resistor M is connected inshunt with the armatures for controlling the dynamic braking anddeceleration of armatures 36A and 31A. It should be noted that theportion of the resistor M bearing the reference numeral rl remains inshunt relation to the armatures at all times and that the dynamicbraking and deceleration of the armatures is controlled by including andexcluding other portions of the resistor M in the shunt circuit aroundthe armature.

Two pairs of contact members SC and SO which may be connected to anysuitable part of the car control system (not shown) are provided forcontrolling the energization of the door opening relay and the doorclosing relay.

A series resistor K and a resistor'relay RS for controlling it areprovided for the motor circuit so that the motors remain energized witha small torque to keep the car doors tightly closed while the car ismoving until it arrives at a landing.

A door opening relay OR and a door closing relay CR are provided forcontrolling the circuit to the motors 36 and 31.

An operation of the door operating system may be assumed as follows: Itwill be assumed that the car 25 has moved into and stopped at the floorlanding served by the hatchway door 15 and that the car door andhatchway door are in their closed position. It will be assumed now thatthe open-door contact members SO are closed to efiect the opening of thecar door and the hatchway door. The closing of the contact members SOenergizes the door opening relay OR by the circuit L+, SO, OR, EOL, orFOL to L. The energized relay OR closes its contact members OR! and CR2and opens its contact members CR3 and ORA. The opening of CR3 and CR4prevents the contact members controlled by the closing of the door frombeing effective while the door is opening. The closing of the contactmembers ORI and CR2 energizes the armatures and field windings of themotors 36 and 31 by the following circuit: L+ in parallel through 33Aand 31A, through 0R2, through field windings 36F and 31F in parallel,through OR! to- L'. The motors 36 and 31 are so wound that thisenergization causes the motor 36 to rotate in thedirection of the arrow95 and the motor 31 to rotate in the direction of the arrow 96.

The rotation of the motor 36 in the direction indicated causes the belt42 to rotate the sheave 43 in the direction of the arrow 91 whichin turncauses the V belt 46 and the cable .46 to rotate the sheave 50 in thedirection of the arrow 98 and at the same time to pull the car doorsection 21 from its closed position toward its open position. Therotation of the sheave 50 causes the sprocket wheel 53 to operate thechain 54 for rotating the controller E to operate its contact membersE01 and E02 when the door section reaches certain predetermined points.The rotation of the motor 31 in the direction of the arrow 95 causes thesheave Bl to rotate in the direction of the arrow 99, thereby drivingthe V belt 63 and the cable 68 to move the car door section 28 from itsclosed position to its open position. The operation of the V belt 63 andthe cable 58 also rotate the sheave 66 in the direction of the arrowI99, thereby rotating the sprocket wheel 10 to operate the sprocketchain 1| and thus in turn, the controller F to operate its contactmembers F01 and F02 when the door section reaches certain predeterminedpoints.

Inasmuch as the operating vanes 15 and 19 are disposed in the notches 16and 30 in the blocks 18 and 8| on the hatchway door sections, theopening movement of the car door sections effects a similar opening ofthe hatchway door sections, and it will be observed that the forcesutilized in opening the hatchway doors are applied in oppositedirections so that the forces are balanced against each other on the carand the car is not subjected to any side motion or side sway, as wouldbe the case in a door operating mechanism pushing against only one doorsection.

It will be assumed now that the car door section 21 reaches thepredetermined slowdown point for decelerating the door sections in theiropening movement slightly ahead of the other car door section 28. Thisoperation of the car door section 21 causes its controller E to closeits contact members E01 thereby short 'circuiting the resistor sectionsr3, M and T5 in shunt with the motor armatures 36A and 31A so as toprovide a shunt path from the supply conductor L+ through the resistorsections 1'! and 12. This action causes the motors 36 and 31 todecelerate both doors to the'desired predetermined slowdown speed. Asboth doors continue toward their full open position, it will be assumedthat the car door section 28 arrives at the next deceleration pointahead of its cooperating door section 21, thus causing its controller Fto close its contact members F02, thereby eliminating the resistorsection 12 from the shunt circuit around the armatures 36A and 31A. Thisaction decreases the speed of both motors 33 and 31 still further totheir stopping speed. Inasmuch as the hatchway door sections 16 and I1are coupled to the car door sections by the clutches 13 and 14, theywill be decelerated to the same rate of speed at the same point.

It will be assumed now that the doors are moving into their full openposition and that car door 21 slightly precedes its cooperative car doorsection 28. At the stopping point, the car door 21 operates thecontroller E to open its contact members EOL in the circuit of the dooroperating relay OR, but nothing happens because that circuit may stillextend through the remaining closed contact members FOL controlled bythe controller F, actuated by the door section 28. It will be assumednow that the door section 28 follows the arrival'of the door section 21in its full open position and thereby operates its. controller F to openits contact members FOL. The opening of these contact membersdeenergizes the re lay OR which opens its-contact members OR! and CR2.thereby deenergizing and stopping the motors 36 and 31.

It will be assumed now that, after a short stay at the floor,theattendant on the car causes the contact members S0 to be opened andthen causes the contact members SC to be closed, to effect the closingof the door. The closing of the contact members SC energizes the doorclosing relay CR by the circuit L+, SC, CR, and L- and also energizesthe resistor relay RS by the circuit L+, SC, RS, and either ECL or FCLto L. The energized relay RS closes its contact members RSI to shortcircuit the resistor K in the door closing circuit of the motors 36 and31. The energization of the relay CR closes its contact members CRI andCR3 and opens its contact members CR2 and CR4. The opening of thecontact members CR2 and CR4 prevents the contact members controlled bythe opening of the door from being efiective while the door is closing.The closing of the contact members CRI and CR3 energizes the armatures36A and 31A and the field windings 36F and 31E of the motors 36 and 31,thus causing those motors to rotate opposite to the direction of thearrows 95 and 96.

The rotation of the motor 36 in a direction opposite to the arrow 95rotates the sheave 43 opposite to the direction arrow 91, thus causingthe V belt 46 and the cable 46A to pull the car door section 21 towardits closed position. The rotation of the motor 31 in the directionopposite to the direction of the arrow 96 causes sheave 6| to rotateopposite to the arrow 99 and thus cause the V belt 63 and the cable 68to pull the door section 28 toward its closed position. The closingoperation of the doors causes the sheaves 50 and 66 to rotate thecontrollers E and F for the closing control operation. It will beassumed that the car door section 28 arrives at its predeterminedslowdown point ahead of the door section 21, thus causing the controllerF to close its contact members FCI, thereby eliminating the resistorsection r5 from the shunt circuit around the armatures 36A and 31A,thereby decelerating both motors 36 and 31. It will be assumed that thedoors travel at a decreased speed and that door section 21 arrives atthe next slowdown point slightly ahead of the door section 28. Thisaction causes the controller E to be operated to the point where itcloses its contact members EC2, thus eliminating resistor section r4from the shunt circuit around the armatures 36A and 31A. This actioncauses both motors to decelerate to their final door closing speed.

It will be assumed now that the car door section 28 arrives at its fullclosed position ahead of the car door 21. This causes the controller Fto open its contact members FCL, but the relays CR and SR still remainenergized because of the parallel contact members ECL. It will beassumed now that the car door section 21 reaches its full closedposition. This operates the controller E to open its contact membersECL, thereby deenergizing the resistor relay RS which opens its con tactmembers RSI, thereby inserting the resistor K in series with the doorclosing circuit of the motors 36 and 31. The contact members SC will notbe opened until the car makes the next stop and the door is to beopened. Inasmuch as the door closing relay CR remains energized untilthe contact members SC are opened, the car door sections 21 and 28 willbe maintained in their closed position by the energized motors 36 and31, but the resistor K will cause a greatly reduced current flow throughthe motors, thus'retaining a small torque in them just sufficient tokeep the doors tightly closed so that the vanes 15 and '19V will be inthe proper position to engage the hatchway door driving blocks at thenext floor landing at which a'stop is made.

It may be observed that usually in normal operation the door sectionswill reach their decelerating switches and limit switches at the sametime, particularly in view of the tie-together cables 84 and 85 on thehatchway door sections. But there may be times when the doors will notoperate quite normally because of wear or other inaccuracies in thesheaves, tracks, etc., and will operate as described. In either case thedeceleration and stopping of the motors will be efiected in the mostdesirablemanner.

How-ever, if the car door sections are operated while the car is betweenfloors, as they will be at times when making operating repairs,inspections, etc., during maintenance work, then the car door sectionsare very likely to arrive at unequal times at their deceleratingswitches and limit switches. The circuits described for the motors willtake care of the inequalities of operation in either case and cause thedoor sections to be operated smoothly by the two motors at all times.

By the foregoing operation, it will be seen that I have provided a dooroperating system in which the motive means may be mounted on the car foroperating a pair of center opening doors on the car and the centeropening doors at any floor landing at which the car may stop in suchmanner that all the parts of the apparatus involved will be so tiedtogether that they will operate as a unit regardless of any small lostmotion or minor application of force which may occur in the system. Itwill further be obvious that with my improved system the forces appliedfrom the car to open or close the hatchway doors will be applied inopposite directions so as to offset each other and prevent any tendencyfor the car to sway from one side to another when the doors are beingopened or closed.

It will also be apparent that my door operator permits the use of a pairof light weight resilient clutches which will stand up in service muchbetter than the usual strong heavy clutch heretofore required in highspeed or medium speed operators.

Although I have illustrated and described only one specific embodimentof my invention, it is to be understood that changes therein andmodifications thereof may be made without departing from the spirit andscope of my invention.

I claim as my invention:

1. In an elevator system, a car for serving a floor landing in ahatchway, a center opening hatchway door comprising a pair ofhorizontally slidable door sections mounted at the landing, and powermeans mounted on the car for individually engaging the hatchway doorsections when the car is at the floor and moving them in oppositedirections to close or open the door.

2. In an elevator system, a car for serving a floor landing in a.hatchway, a center opening hatchway door comprising a pair ofhorizontally slidable door sections mounted at the landing, a pair ofclutches supported on the car, one clutch for each door section, motivemeans mounted on the car, and means responsive to operation of themotive means for moving the clutches in opposite directions intoengagement with the door sections to effect an opening or a closingmovement thereof when the car is at the floor landing.

' 3. In an. elevator system, a, car for serving a floor landingin ahatchway; a hatchway door comprising ,a pair of center openinghorizontally slidable door sections, a pair of clutches supported .onthe car, one for each door section, a pair of motors mounted on the car,one for each clutch, means for connecting both motors to a source ofelectrical energy to cause them to rotate simultaneously in oppositedirections, and means responsive to rotation of the motors in oppositedirections when the car is at the landing for causing the clutches tomove in opposite directions into engagement with the hatchway doorsection when the car is at the landing, and thereby opening or closingthe hatchway door.

4. In an elevator system, a car ior serving a floor landing in ahatchway, a hatchway door comprising a pair of center openinghorizontally slidable door sections, a pair of clutches supported on thecar, one for each door section, a pair of motors mounted on the car, onefor each clutch, means for connecting both motors to a source ofelectrical energy to cause them to ro tate simultaneously in oppositedirections, means responsive to rotation of the motors in oppositedirections when the car is at the landing for causing the clutches tomove in opposite directions into engagement with the hatchway doorsections when the car is at the landing, and thereby opening or closingthe hatchway door, a pair of sheaves mounted at the hatchway door,flexible means disposed on the sheaves and connected to each of thehatchway door sections to cause each section to move 'in accordance withthe movement of the other section, and a lock responsive to operation ofone of the hatchway door sections for locking the hatchway door in itsclosed position.

- 5. In an elevator system having a car serving a floor landing in ahatchway, a hatchway door for the landing comprising a pair of centeropening horizontally slidable door sections, a door on the carcomprising a pair of center opening horizontal-1y slidable doorsections, motive means mounted on the car for moving the car doorsections in opposite directions in opening or closing them, and a clutchmounted on each car door section for engaging the hatchway door sectionopposite that car door section and moving it with itself when the car isat the landing and the motive means is energized to move the car doorsections in an opening or closing operation.

6. In an elevator, a car for serving a corridor opening, a hatchway doorcomprising a pair of center opening horizontally slidable door sectionsmounted at the corridor opening, a car door comprising a pair of centeropening horizontally slidable door sections mounted on the car, anindividual motor mounted on the car for each car door section, means foroperatively connecting each motor to its door section, means forconnecting both motors to a source of electrical energy to cause them torotate simultaneously in opposite directions for moving the car doorsections in opposite directions, and a clutch mounted on each car doorsection for engaging the hatchway door section opposite that car doorsection and moving it with itself when the car is at the hatchway doorand the motors are energized to move the car door sections in an openingor closing operation.

7. In an elevator, a car for serving a corridor opening, a hatchway doorcomprising a pair of center opening slidable door sections mounted atthe corridor opening, a car door comprising a pair of center openingslidable door sections mounted on the car, an individual motor mountedon thecar for each car door section, means for connecting both motors toa source of electrical energy to cause them to rotate simultaneously inopposite directions for moving the car door sections inoppositedirections, a pair of limit switches responsive to operation of the cardoor sections for simultaneously disconnecting both -motors from theirsource of power only when opening, a hatchway door comprising a pair ofcenter opening horizontally slidable door sections mounted at thecorridor opening, a car door comprising a pair of center openinghorizontally slidable door sections mounted on the car, an individualmotor mounted on the car for each car door section, means for connectingboth motors to a source of electrical energy to cause them to rotatesimultaneously in opposite directions for moving the car door sectionsin oppo- .site directions, a pair of limit switches responsive tooperation of the car door sections for simultaneously disconnecting bothmotors from their source of power only when both car door sectionsarrive at predetermined points in their travel, a clutch mounted on eachcar door section for engaging the hatchway door section opposite thatcar door section and moving it with the car door section when the car isat the hatchway door and the motors are energized to move the car doorsections, a pair of sheaves mounted at the hatchway door, a flexibleconnecting means disposed over the sheaves and connected to eachhatchway door section for causing the hatchway door sections to travelcorresponding distances, and a lock responsive to operation of one ofthe hatchway door sections for locking the hatchway door.

9. In an elevator, a car for serving a corridor opening, a hatchway doorcomprising a pair of center opening horizontally slidable door sectionsmounted at the corridor opening, a car door comprising a pair of centeropening horizontally slidable door sections mounted on the car, anindividual motor mounted on the car for each car door section, means forconnecting each motor to its door section, means for connecting bothmotors to a source of electrical energy to cause them to rotatesimultaneously in opposite directions for moving the car door sectionsin opposite directions, a clutch mounted on each car door section forengaging the hatchway door section opposite that car door section andmoving it with itself when the car is at the hatchway door and themotors are energized to move the car door sections in an opening orclosing operation, a pair of sheaves mounted at the hatchway door, and aflexible means disposed on the sheaves and connected to both hatchwaydoor sections to provide a tie between the two motor drives forabsorbing any minor unbalance and assuring that each part of the systemcompletes its motion simultaneously with the other parts.

10. In an elevator system, a car for serving a floor landing in ahatchway, a car door compris ing a pair of center opening horizontallyslidable means responsive to the first one of either door sections toarrive at its slow down point for decelerating both motors.

11. In an elevator system, a car for serving a floor landing in ahatchway, a car door comprising a pair of center opening horizontallyslidable door sections, a pair of motors mounted on the car, one foreach door section, means for operatively connecting each motor to itsdoor section, a circuit for simultaneously connecting both motors to asource of electrical energy to cause them to rotate simultaneously inopposite directions for moving the door sections in opposite directionsin an opening operation, and means responsive to that door section whichcompletes its opening movement last for disconnecting both motors fromtheir source of energy.'

12. In an elevator system, a car for serving a floor landing in ahatchway, a car door comprising a pair of center opening horizontallyslidable door sections, a pair of motors mounted on the car, one foreach door section, means for operatively connecting each motor to itsdoor section, a circuit for simultaneously connecting both motors to asource of electrical energy to cause them to rotate simultaneously inopposite directions for moving the door sections in opposite directionsin a closing operation, and means responsive to that door section whichcompletes its closing movement last for decreasing the supply of energyto both motors.

13. In an elevator system, a car for serving a corridor opening, a cardoor comprising a pair of center opening slidable door sections mountedon the car, an individual motor mounted on the car for each doorsection, means for operatively connectingeach motor to its door section,means tion to arrive at a predetermined position for decelerating bothmotors, and means responsive to the last door section to arrive at asecond predetermined position for decelerating both motors.

14. In a power operated mechanism for opening and closing elevator carand hatchway openings, the combination of a pair of hatchway doorsections for closing the hatchway opening, said door sections beingmovable from a center position in opposite directions, gearing forcausing said doors to move in synchronism, a pair of door sections forclosing the car opening, also movable from a center position in oppositedirections, an independent power operator for each of said car doorsections for moving said door sections independently, and means forengaging said car door sections with said hatchway door sections tothereby cause said car door sections to move in synchronism.

15.- In a door operating mechanism for center-opening, bi-parting doorsfor an elevator car entrance and for an associated hatchway entrance,the combination of a pair of doors for said car, movable from a centerposition in oppositedirections to open said car entrance, a pair ofdoors for said hatchway entrance, movable from a center position inopposite direction to open said hatchway entrance, means mounted partlyon said car doors and partly on said

